AMIS-732128 Datasheet, PDF (4/9 Pages) AMI SEMICONDUCTOR – 50μm-pitch Wide Aperture Spectroscopic Photodiode Arrays

AMIS-732128, AMIS-732256, AMIS-732512
50µm-pitch Wide Aperture Spectroscopic Photodiode Arrays
Data Sheet
4.0 Self-Scanning Circuit
Figure 5 shows a simplified electrically equivalent circuit diagram of the photodiode array. An MOS read switch connects every
photodiode in the array to a common output video line. Incident photons generate electron charge that is collected on each imaging
photodiode while the switch is open. The shift register is activated by the start pulse. A pulse propagates through each shift register
stage and activates the MOS read switches sequentially. As the shift register sequentially closes each read switch, the negative stored
charge, which is proportional in amount to the light exposure, from the corresponding photodiode, is readout onto the video line, QOUT.
Typically, an external charge-integrating amplifier senses the negative output charge on the video line from each photodiode pixel. The
shift register continues scanning the photodiodes in sequence, until the last shift register stage is reach, at which time the fourth and
last dummy pixel is read out and end-of-scan (EOS) output is held high for one clock cycle. The next start pulse can then restart the
shift register.
Figure 5: Simplified Circuit Diagram of a WSN Photodiode Array
AMI Semiconductor – Dec. 05, M-20491-001
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